Rather than match the web client behavior (removing labels) when
messages are appended to trash, we simply omit the check to see if the
message in trash is present in other labels.
This will produce the same end result and will resolve the issue of
users not being able to fully delete their messages.
Add special case handling for draft messages so that if a Draft is
updated via an event it is correctly updated on the IMAP client via a
the new `imap.MessageUpdated event`.
This patch also updates Gluon to the latest version.
Only delete messages when unlabeled from trash/spam if they only exists
in All Mail and (spam or trash).
This patch also ports delete_from_trash.feature and use status rather
than fetch to count messages in a mailboxes.
